从最高到最低排序多个数组

Question

I'm displaying data from multiple JSON files using an array and using sort(); to sort the values of ID from highest to lowest.

The problem I'm facing is that sort(); is ordering both arrays separately, causing the following will be outputted:

• 11
• 9
• 7
• 56
• 12
• 5

11, 9 and 7 (the first array ) are sorted and 56, 12 and 5 (the second array) are sorted. How do I merge the arrays so that the following is outputted:

• 56
• 12
• 11
• 9
• 7
• 5

Here's my JSON array:

$homepage = array();
$homepage[] = '{
  "info": {
    "collection": [
      {
        "ID": "7"
      },
      {
        "ID": "9"
      },
      {
        "ID": "11"
      }
    ]
  }
}';
$homepage[] = '{
  "info": {
    "collection": [
      {
        "ID": "12"
      },
      {
        "ID": "56"
      },
      {
        "ID": "5"
      }
    ]
  }
}';

Here's where I decode the JSON array, sort it and echo it:

foreach ($homepage as $homepage2) {
$data = json_decode($homepage2, false);

usort($data->info->collection, function ($a, $b) {
    return $b->ID - $a->ID;
});

foreach($data->info->collection as $key) {
    echo'
    '.$key->ID.'
    ';
}
}

Answer 1

First you need to decode those jsons to arrays and add them to for example $homepage_decoded ...

$homepage_decoded = array();
foreach($homepage as $hp)
   $homepage_decoded[] = json_decode($hp,true);

$merged = array_unique(call_user_func_array('array_merge', $merged));

And then sort $merged ...

sort($merged,SORT_NUMERIC);

Excuse me if there is some syntax error in code I given, writting it from phone. But idea should be clear.